Claude Sonnet 4 now supports 1M token context in Vercel AI Gateway

You can now leverage Claude Sonnet 4's updated 1 million-token context window with Vercel's AI Gateway with no other provider accounts required. This release from Anthropic enables significantly larger inputs such as full codebases (~75,000+ lines) or large document sets.

AI Gateway lets you call the model with a consistent unified API and just a single string update, track usage and cost, and configure performance optimizations, retries, and failover for higher than provider-average uptime.

To use it with the AI SDK v5, start by installing the package:

pnpm i ai

Then set the model to anthropic/claude-4-sonnet:

import { streamText } from 'ai';
import { largePrompt } from './largePrompt.ts';

const result = streamText({
  headers: {
    'anthropic-beta': 'context-1m-2025-08-07',
  },
  model: 'anthropic/claude-4-sonnet',
  prompt: `You have a big brain. Summarize into 3 sentences: ${largePrompt}`,
  providerOptions: {
    gateway: { only: ['anthropic'] },
  },
});

Includes built-in observability, Bring Your Own Key support, and intelligent provider routing with automatic retries.

To deliver high performance and reliability to Claude Sonnet 4, AI Gateway leverages multiple model providers under the hood, including Anthropic and Bedrock.

Learn more about AI Gateway and view the new AI Gateway model leaderboard.